1. Field of the Invention
The present invention relates generally to an absorbent article, and more particularly to an absorbent article having a pulpless absorbent core. The absorbent article includes features that provide good leakage performance and rewet values.
2. Description of Related Art
Absorbent products, such as baby diapers, have a 90% to 95% market penetration in the United States and Europe. In contrast, the levels of market penetration in some emerging market countries, such as China and India, are less than 5%. Part of the reason for these low levels of market penetration is the relatively high cost of the absorbent products in those markets. Accordingly, manufacturers of absorbent products in the emerging market countries face an enormous challenge in trying to find ways to produce low cost, but effective, products.
Reducing the amount of raw materials in the absorbent products is one strategy to reduce the overall cost. The cost of raw materials may comprise up to 80% of the total cost in manufacturing the absorbent products. In order to produce a functional product, however, a minimum amount of conventional materials needs to be employed. If a manufacturer reduces the amount of material used beyond such minimum, the functionality of the product may be compromised and the acceptance of the product by consumers could be greatly diminished. For example, it is well known that the most important consumer attributes for baby diapers are leakage control and dryness. Accordingly, reducing the cost of producing baby diapers by reducing raw materials should not compromise the effectiveness of the diapers in controlling leakage and maintaining dryness.
Conventional baby diapers typically are constructed with a moisture-impervious outer backing sheet, a moisture-pervious body contacting inner liner sheet, and a moisture-absorbent core sandwiched between the liner and backing sheet. The absorbent core of these conventional diapers includes fluff pulp and water-absorbing polymers, each serving a different purpose. The fluff pulp in the absorbent cores provides quick absorption of liquids to prevent leakage during an initial insult. Maintaining long term dryness can be accomplished by the slower acting water-absorbing polymers that provide for a more permanent liquid storage and a high absorbency-under-load (AUL). Optimization of these properties may be accomplished by varying amounts and ratios of the pulp and polymer.
Conventional baby diaper cores that contain a fibrous web of fluff pulp and water-absorbing polymers typically maintain adequate polymer efficiency if the core contains less than about 50% water-absorbing polymer. Fluff/polymer diaper cores containing more than 50% water-absorbing polymer generally result in lower polymer efficiency because of gel blocking. Although fluff/polymer cores at greater than 50% polymer can provide adequate absorbency, the overall basis weight of the core typically must be increased to compensate for the lower efficiency of the polymer. Increasing the basis weight decreases the performance/cost ratio of the absorbent core, making them uneconomical. Also, increased basis weights tend to affect the fit and comfort of the garment, as well as impacting the packaging and shipping cost.
Accordingly, there is a need in the art for a cost effective absorbent garment which uses less materials, maintains good leakage performance, and has a long term dryness profile that will provide for a much more comfortable and hygienic product.
The description herein of various advantages and disadvantages of certain elements of known absorbent articles is in no way intended to limit the scope of the invention to the inclusion or exclusion of these elements. Indeed, certain aspects or features of embodiments may include one or more of these elements, without suffering from the disadvantages.